International consensus on a proposed score system for muscle biopsy evaluation in patients with juvenile dermatomyositis: A tool for potential use in clinical trials

Lucy R. Wedderburn, Hemlata Varsani, Charles K.C. Li, Katy R. Newton, Anthony A. Amato, Brenda Banwell, Kevin E. Bove, Andrea M. Corse, Alison Emslie-Smith, Brian Harding, Jessica Hoogendijk, Ingrid E. Lundberg, Suely Marie, Carlo Minetti, Inger Nennesmo, Elisabeth J. Rushing, Caroline Sewry, Susan C. Charman, Clarissa A. Pilkington, Janice L. Holton

Research output: Contribution to journalArticle

Abstract

Objective. To devise and test a system with which to evaluate abnormalities on muscle biopsy samples obtained from children diagnosed with juvenile dermatomyositis (DM). Methods. We established an International Consensus Group on Juvenile DM Biopsy and carried out 2 phases of consensus process and scoring workshops. Biopsy sections (n = 33) were stained by standard methods. The scoring tool was based on 4 domains of change: inflammatory, vascular, muscle fiber, and connective tissue. Using a Latin square design, biopsy samples were scored by 11 experts for items in each domain, and for a global abnormality measure using a 10-cm visual analog score (VAS 0-10). The tool's reliability was assessed using an intraclass correlation coefficient (ICC) and scorer agreement (α) by determining variation in scorers' ratings. Results. There was good agreement in many items of the tool, and several items refined between the meetings improved in reliability and/or agreement. The inflammatory and muscle fiber domains had the highest reliability and agreement. The overall VAS score for abnormality had high agreement and reliability, reaching an ICC of 0.863 at the second consensus meeting. Conclusion. We propose a provisional scoring system to measure abnormalities on muscle biopsy samples obtained from children with juvenile DM. This system needs to be validated, and then could be used in prospective studies to test which features of muscle pathology are prognostic of disease course or outcome. We suggest that the process we used could be a template for developing similar systems in other forms of myositis.

Original languageEnglish (US)
Pages (from-to)1192-1201
Number of pages10
JournalArthritis Care and Research
Volume57
Issue number7
DOIs
StatePublished - Oct 15 2007

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Keywords

  • Histopathology
  • Juvenile dermatomyositis
  • Muscle biology
  • Myositis
  • Pediatric rheumatology

ASJC Scopus subject areas

  • Rheumatology

Cite this

Wedderburn, L. R., Varsani, H., Li, C. K. C., Newton, K. R., Amato, A. A., Banwell, B., Bove, K. E., Corse, A. M., Emslie-Smith, A., Harding, B., Hoogendijk, J., Lundberg, I. E., Marie, S., Minetti, C., Nennesmo, I., Rushing, E. J., Sewry, C., Charman, S. C., Pilkington, C. A., & Holton, J. L. (2007). International consensus on a proposed score system for muscle biopsy evaluation in patients with juvenile dermatomyositis: A tool for potential use in clinical trials. Arthritis Care and Research, 57(7), 1192-1201. https://doi.org/10.1002/art.23012